1. Field of the Invention:
The present invention relates generally to a precious metal recovery system utilizing an amalgamation process which assures substantially complete recovery both of the precious metal sought and of the mercury needed for performing the process.
2. Description of the Prior Art:
Alloys of mercury with other metals, for example, silver, gold, cesium, zinc, or alkali metals have long been known. The knowledge that such alloys are readily formed was used by the Romans to extract precious metals such as silver and gold from silver and gold bearing ores when extraction was otherwise difficult or impossible to achieve. According to this process, known as amalgamation, the ore containing the particular metal sought is immersed in mercury or otherwise subjected to contact with mercury. The mercury surrounds the metal sought and forms an alloy with it known as an amalgam. Centuries after the Romans, the Spaniards extensively used the process in exploiting the metallic treasures of the New World.
In recent years, various attempts have been made to modernize and automate the amalgamation process. One such recent attempt is reflected in the Micron Gold Amalgamator Model 2000 invented by Alvin C. Hurd of Coachella, California and publicly known at least as early as February 1984. The apparatus thereby disclosed operates to force feed precious metal bearing ore, in a slurry mixture, through a bed of mercury to form an amalgam. The amalgam is withdrawn and the mercury subsequently separated out to yield of the precious metal. Unfortunately, that process and other known amalgamation processes have required handling of the mercury by personnel without proper safeguards either to the personnel or to the environment, even though it has long been known that mercury is a deadly poison and therefore possesses severe undesirable health and environmental characteristics.